# ARCHIVED ARCHIVED ARCHIVED
This crate is archived and will not be updated.

The code is now at
[`safina::threadpool`](https://docs.rs/safina/latest/safina/threadpool/index.html) in the
[`safina`](https://crates.io/crates/safina) crate.

----

# safina-threadpool

A threadpool.

You can use it alone or with [`safina`](https://crates.io/crates/safina),
a safe async runtime.

# Features
- Add a closure or `FnOnce` to the pool and one of the threads will execute it
- Automatically restarts panicked threads
- Retries after failing to spawn a thread
- Drop the `ThreadPool` struct to stop all idle threads.
- Destroy the pool and wait for all threads to stop
- `forbid(unsafe_code)`
- Depends only on `std`
- 100% test coverage

# Limitations
- Not optimized

# Examples
```rust
let pool =
    safina_threadpool::ThreadPool::new("worker", 2).unwrap();
let receiver = {
    let (sender, receiver) =
        std::sync::mpsc::channel();
    for data in data_source {
        let sender_clone = sender.clone();
        pool.schedule(
            move || process_data(data, sender_clone));
    }
    receiver
};
let results: Vec<ProcessResult> =
    receiver.iter().collect();
// ...
```

# Alternatives
- [`blocking`](https://crates.io/crates/blocking)
  - Popular
  - A little `unsafe` code
  - [blocking/issues/24: Recover from thread spawn failure](https://github.com/smol-rs/blocking/issues/24)
- [`threadpool`](https://crates.io/crates/threadpool)
  - Popular
  - Well maintained
  - Dependencies have `unsafe` code
  - [rust-threadpool/issues/97: Feature: provide a way to shutdown the thread pool](https://github.com/rust-threadpool/rust-threadpool/issues/97)
  - Panics when failing to spawn a thread.
- [`scoped_threadpool`](https://crates.io/crates/scoped_threadpool)
  - Popular
  - Contains `unsafe` code
  - Unmaintained
  - Does not restart workers on panic.
- [`scheduled-thread-pool`](https://crates.io/crates/scheduled-thread-pool)
  - Used by a popular connection pool library
  - Dependencies have `unsafe` code
  - Schedule jobs to run immediately, periodically, or after a specified delay.
- [`workerpool`](https://crates.io/crates/workerpool)
  - Dependencies have `unsafe` code
- [`threads_pool`](https://crates.io/crates/threads_pool)
  - Full of `unsafe`
- [`thread-pool`](https://crates.io/crates/thread-pool)
  - Old
  - Dependencies have `unsafe` code
- [`tasque`](https://crates.io/crates/tasque)
  - Dependencies have `unsafe` code
- [`fast-threadpool`](https://crates.io/crates/fast-threadpool)
  - Dependencies have `unsafe` code
- [`blocking-permit`](https://crates.io/crates/blocking-permit)
  - Full of `unsafe`
- [`rayon-core`](https://crates.io/crates/rayon-core)
  - Full of `unsafe`

# Changelog
<details>
<summary>Changelog</summary>

- v0.2.4 - Update docs.
- v0.2.3 - Implement `From<NewThreadPoolError>` and `From<TryScheduleError>` for `std::io::Error`.
- v0.2.2 - Add `ThreadPool::join` and `ThreadPool::try_join`.
- v0.2.1 - Improve test coverage.
- v0.2.0
  - `ThreadPool::new` to return `Result`.
  - `ThreadPool::try_schedule` to return an error when it fails to restart panicked threads.
  - `ThreadPool::schedule` to handle failure starting replacement threads.
- v0.1.4 - Stop threads on drop.
- v0.1.3 - Support stable Rust!  Needs 1.51+.
- v0.1.2 - Add another example
- v0.1.1 - Simplified internals and improved documentation.
- v0.1.0 - First release

</details>

# TO DO
- Make `join` and `try_join` work with `Arc<ThreadPool>`.
- Log a warning when all threads panicked.
- Update test coverage.
- Add a public `respawn_threads` function.
- Add a stress test
- Add a benchmark.  See benchmarks in <https://crates.io/crates/executors>
- Add a way for a job to schedule another job on the same thread, with stealing.